When you cannot update your Nokia Phone Firmware normally using OVI Suite probably due to dead phone, you need to make your phone back alive by manually flashing the firmware using JAF or Pheonix. JAF flashing software is more preferable by peoples. Also not to flash only original Nokia Firmware but to install modded or ported CFW (Cooked/Customized FirmWare).
Here I just want to share what the firmware files contain.
Nokia firmware can be downloaded using Navifirm.
When you downloaded the firmware files, you will get *.uda.fspx, *.core.Cxx, *.rofs2.Vxx, *.rofs3.fpsx and other side files.
Uda contains files that will bw placed in phone memory or called drive C:/.
Core file or rofs1 file is the main files containing the operating system.
Rofs2 mainly contains languages for the firmware.
Rofs3 contains custom files like theme etc.
All rofs file will be placed in read only section, drive Z:/
With the priority core > rofs2 > rofs3 ,
Core will be installed first, duplicate files contained in core and rofs2 will be replaced with files in rofs2.
And duplicate files contained in rofs2 and rofs3 will be replaced with files in rofs3.
After flashing, rofs files will be read only and will stay even after hard reset your phone unless reflashing with other firmware.
PNHT created a program called Nokia Firmware Editor that has capability to edit firmware files.
Editing firmware is so dangerous if you dont know what actually what are you doing.
Like I did before, after I edit and flash, my phone able to boot but when I try to access main menu, “system error” message poped-up. Then I reflash with the original CFW I downloaded from the net.
Another advice is, flashing your phone is really risky, you may brick your phone. But I think if you brick your phone, you still can repair it, refer here